1. Field of Invention
The present invention relates generally to the crushing, grinding, comminuting or similarly processing of materials such as mineral ores, rock and the like, and more particularly to apparatus for use in such processing.
2. Description of Related Art
Grinding mills are one form of apparatus used for processing materials as described above. Typical grinding mills are generally comprised of a drum shaped shell mounted for rotation about its central axis. The axis of the shell is generally horizontally disposed or slightly inclined towards one end. The interior of the shell forms a treatment chamber into which the material to be processed is fed. In one form of mill a grinding medium such as balls or rods is placed in the treatment chamber with the material to be processed. During rotation of the shell the grinding medium impacts on the material under the effects of gravity to cause the crushing or grinding action. The grinding medium and material to be processed are carried up the side of the shell whereafter it falls to the bottom of the shell. To assist in lifting the material up the side of the shell lifter bars are often provided which are secured to the interior surface of the shell. The lifter bars extend generally longitudinally of the shell and are circumferentially spaced apart around the inner surface.
In order to protect the inner surfaces of the shell from damage during the grinding process, liners are often provided on the inner surface of the shell. These liners take many forms. FIGS. 1 and 2 of the specification illustrate one conventional form of liner assembly. The liner assembly generally indicated at 10 comprises a mounting element 12 having a base wall 13 and a sidewall 14 forming a recess 15 with an open side which receives a cushioning element 16 therein. A wear element 18 is fitted for example by chemical bonding to the cushioning element 16. The base wall 13 of the mounting element 12 is adapted to be secured to the inner face of the shell by fastening bolts.
The elastomeric cushion's main purpose is to absorb and disperse impact forces which arise as a result of wear elements being struck by the grinding medium and the material being processed inside the shell as it rotates. As best seen in FIG. 2, due to the configuration of the mounting element 12, lateral deformation of the elastomeric cushion is restricted and as such its deflection D resulting from the application of an impacting force FI to the wear element is limited to the vertical direction and its ability to absorb or disperse the impact energy is significantly reduced. This results in a shorter useful life for the wear elements.